Method of projecting moving pictures and moving-picture-projecting machines



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METHOD OF P ROJECTNG MOVING PICTURES AND MOVING PICTURE PROJ Feb. `16 1926.

s. BARDY METHOD OF PROJEOTNG MOVING PICTURES AND MOVING PICTURE PROJECTING MACHINES Filed March a, 1921 6 Sheets-Sheet E w/m/Ess.-

METHOD OF PROJECTING MOVING PICTURES AND MOVING PlCTURE FROJECTNG MACHINES W? FTA/ESS.

ffy/f7 Y Fem N5 i925, LS'BA-BS s. BARDY METHOD OF PROJECTNG MOVNG PICTURES AND MOVTNG PICTURE PROJECTNG MACHINES WMI/1MM Feb. 16 w26.

S. BARDY METHQD 0F PROJECTING MOVING PICTURES AND MovING PICTURE EROJECTING MACHINES FiIed March 8;

1921 6 Sheets-Sheet 6 /07 ET Vj.

fof F/G. A2.

/09 l Q Iza sa /OD/Ol Q E l //2 /A/VENTO/P Samuc/qra/y W/mffss.- g

dilterences Patented hielo, 19260 unirse istante SMUELBRDY, 0F PHLDELEEEA, PENNSLVNI, ASSG'NOR, BZiMESNE ASSIGN- JMIEN'JS, TO BAB/DY PROJECTOR GG., 0F PELADELJ-IA, PENNSYLVANIA, A CDE- V POBATIQN OF DELVBE.

METHOD OF PROJECTEN@ 'OVNG;

ric'rurins hun naci-nnss.

Application filed farcli 8, 1921. Serial lilo. $0,575.

ing is av full, clear, and enact description,r

vreference being had to the accompanying drawings, which form a part of this specification. rllhis invention relates'to an improvement inthe method of projecting moving pictures an'd'nioving picture projecting machines, in

which the filmlstrip is continuously moved and the vobject 1s projected to appear sta tioiiary on the screen bymeans of an optical compensating system which tends to` ymove the picture on the screen in the reverse direction to the movement ot the image, and at the same speed, so that the picture provjectedon the-screen appears to be stationary to the'eye ot' the observer.

lt is generally known to those skilled in the moving picture art that films have a tendency to continually and gradually shrink to an unknown limit, which is at first relatively rapid and decreases as the film ages and dries out. The rate and speed oit said shrinkage varies inL accordance with the temperature and atmospheric condition to which the lilm is exposed,fas well as to in the film structure. rllhis shrinking of films has long been recognized,

' and 'as it is essential to maintain perfect synchronism between `the successive picturesI on the film and the projecting apparatus, it has now become customary to thoroughly age the film before pertorating, so that the further shrinkage thereof will not be suti'icent in length or variation to cause the -iteeth on the lihn feeding sprocket wheels getting out of timed relation with the succ cssive pictures on. the ilin.

rlllhis aging o the films before'perforating has' no doubt overcome to a large extent the evil of the feeding sprocket wheels getting- 4 Seed one-guarter-ogt ai; inch, to the' toot, will not appreciably affect the appearance of the projected picture, when the pictures projected through a machine in which the iihn is intermittently moved between e3 posures and is maintained stationary when exposed. The only optical defect which would be caused by the shrinking of the tilm when pro]ected through an intermittent inachine is the slio'ht increasing and decreasinginthe size ot the picture on the screen, land as this variation is generally relatively gradual throughout the film, and not abrupt, the increasing and decreasing of the-size ot the picture on the screen is also relatively gradual, so thatthe usual observer vwould hardly detect any optical -4defect provided, however, that the shrinkage were notsut- Ycient to cause the film and sprocket wheels to get out of synchronisin.

This, however, is not the case when the .films are projected throughniachines in which the film is continuously moved to expose a given number of pictures per second and in which a 'moving optical system is usedoto compensate for the movement of the nlm.

ln machines or this kind, it is also necessary to maintain synclironisin between the film feeding sprogket wheels and the successive pictures on the film as the'optical compensating system is actuated in timed relation to the eeding'sprockets. Machines of this type have an optical system to comm pensate for the movement of the film which will not interfere with the aplanatic and astigiuatic properties of the relatively fixed rectilinear projection lens.- device such as described in my ?atent No. 1,316,669, issued September 23, 1919, would be ideal if the ratio between the number of pictures and the. length orp the film were the saine throughout the length of the individual` films, as the speed of compensating lens and the lineal speed or" the film would then aiways be constant. lt is well known to those skilled in the manufacture and projection of film that the ratio between the number of pictures and lineal length of tilm is not constant throughout the length ot the film, and in order to project a picture through a machine of this type to prevent flickering, due to variation in the sises of the pictures liti@ on the iilm, it is essentialto provide some means to automatically,compensate Jfor this variation in size.

The object of 4this invention is toy provide a method `and an automatic synchronizing device whicliwill increase and decrease 'the enlargement of the picture conversely in proportion to the variation in the sizes of the pictures on the film caused by the length of the film, so as to'maintain the size of thepictiire projected through or onto the' optical compensating meansv constant and thus correctoptically theI variations in the film shrinkage.

i accomplish this `object by utilizing the variations in speed between the lineal `travel n of the film and the number of pictures pass# ing a given point Vin a given time and provide 'suitable devices actuated by said va 'riations to adjust the-film, projecting lens, and movable optical compensating systemA movement ot'thepictures and compensating device. would be constant. vvIif'the film shrinks' slightly, the lineal travel of the film willv be slower proportionately than the compensating device, so thatV the successive pictures projected onto the 'screen will be moved lon the screen in proportion to the differences between the lineal speed of a standard or normal film and the shrunk film, which causes flicker.

-1 The successive pictures on the film are moved in t'med relationto the compensating device, so that for each picture passed 'between the source of l'glit and the autoniatically adjustabley projecting device there is moved therewith a compensating surface or lens to counteract the movement of the film; The projecting lens is automatically adjusted by devices actuated by the differences between the height of the pictures or length of filmin proportion to the number of pictures caused by the shrinkage, to vary the magnification ofthe pictures in accord ance with the variation in height, to maiiitain the area of light rays passingthrough the pictures constant at the plane at which they. arev intercepted by the compensating surfaces or lenses, so that the light rays passing through the successive pictures are always insynclironisni with the `successive com'jpensatmgsurfaces or lenses. i

'Another object of my invention is to pro- Levaias vide a combined synchronizer and stabilizer yvhich will maintain the lineal speed ot the `film substantially constant, irrespective of slight variations ini'the film length caused' by shrinkage,- wliich will assist in avoiding flicker as well as prevent excessive wear on Athe edges of the perfrations in the film by the teeth on the sproclret'wlieels.

` A still urtlieiyobjectof my invention is to'provlde a sensitive'controlling device for' the'synchronizing mechanism for the-,vas riatioiisiii the lengthof the film which is automatic inits action, which `will readily and `quickly respond to the variations in length,

and readily and quickly cause vthe synchroniziiig mechanism to be set into operation to adjust' the necessary elements of theapparatus 'to compensate for the variations in. that portion of the film passing through the apparatus, as such' variations in lengtlr occui'.

Fig. 1 is a diagram illustrating the general arrangement of an apparatus built in accordance with one form of my invention.

Fig. 2 is a side view of saine, principally iii-section.

Fig. Bris a diagram villustrating the varions electrical connections. l

Fig-4 is a face view of the synchronizn ing mechanism.

Fig. 5 is a sectional plan view illustrating the braking device for the synchronizing motor. j

Fig. 6 is a detail scctional'view on the line 6-6 of Fig. Il. j 4 I Figs. 7 and S are cross-sectional views on the lines 7 and 8 o'tI Fig. 6.

Fig. 9 is a longitudinal sectional view through the adjustable projectinglens system.

Figs. 10 and 11 are detail sectional views on the lines 10 and 11 respectively of Fig. 9.

Fig. 12 is a view of the automatic switch box with the cover removed.

Fig. 1S is a side elevation of an adjustable cani for controlling the positions of the projecting lens members. i

Fig. 14 is a plan view of same.

ln these drawings. the reference character 10 designatesa suitable supportingframe on which'is rotatably mounted a drinn 11 carrying Jfour movable lenses 12, l2", 12C, and 12, each of which in the construction shown is divided into Aa plurality of sections. and which are mounted for adjustment relative to cach other so that the different sect ions will project the lighti'ays to the same point on the screen.

rThe lens drum 11 is rotatably mounted about the axis of a shaft 13 carrying a lihn feed sprocket wheel ll which is provided vwith the proper number of teeth tor feeding four pictures for each revolution or one picture for each of the four compensating ,lenses on the drum 11.

ies-

v pictures with relation to the ]enscs 12L vto 12k.

15 is the film feeding reel nfounted lon a spindle 16 which is provided` with the usualk friction devices for preventing th'e overrunning of the reel, and-17 is the film take-up reel mounted' on ythe spindle 1S. 19 is'a film measuring wheelor synchronizer which is arranged to freely rotate on a spindle QQsupported from the frame 10, and which Wheel forms one ofthe elements of the compensating device.

rllhe film 21 passes from the reel '15 through -a film ygate 220i common construction, about an idler 23, the measuring Wheel 19 and the sprocket `Wheel 14 to the take-up reel 17.

24 arel pressure rollers which are mounted on levers 25 pivotalaly connected to the frame 10, and which rollers are held against the 'filmonth'e measuring Wheel 19 by means of springs 26 to prevent, slip between the film and the measuring Wheel.

' rChe connections between the levers 25 and i .springs 26 are such that when the levers are in thepositions shown 'in Fig. 3 the rollers 2&1Mv will be pressed against the film and vWheel 19, and when the levers 25 are depressed 'the springs 26Will retain the levers against the stops 27 on the frameto permit the removal or positioning of theiilm.- n' A' 'ltnterposed between. the 'lilin gate and the movable or compensating lenses on v the drum '11 is the projecting lens which com prises lenses`28 and 29. f

These lenses 2S and 29 are Amounted on suitable .supports to permit adjustment to- Ward and from the film ,to focus the picture on theiscreen and are also arranged to -be adjusted relative to each other to.compen sate for the varia-tions. in the sizes of the pictures on the film to maintain the projectedpicture a' uniform size to prevent flickenvand are `adjusted by mechanism here inaftei more clearly set forth.

As illustrated.'diagraminatically in 1 and et, the light rays from a suitably located lamp are directed through that portion of the film 21 within the film gate 2e, the projecting lens andthe rectifying lenses 1.2a to 12d to the screen byia suitableprism 30 suitably supported on the frame 10. 'lt-he drum 11 and the sprocket Wheel 14 are connected so as to be rotated together by means of a driving pulley 31 connected tothe drum 11, which is connected by means of a belt ywith a pulley 32 on a motor shaft 33. is a'second pulley on dthe drum 11 which lis connected with. a pulley 35 on 'the spindle 18l of the-take-up reel 17 and Which-is arrangedtO rictoiially drive the-reet 1'? 'to tions to the inotorshaft.

OUl 110195 along each-edge Afor each picture,

and sixteen such sets or pictures for each' foot of tili'n when first, perforated. its the lilnis are now generally tl'ioroughly-dried 'and aged before they are perforated, there is very littlelikelihood` of aiilni shrinking to an extent greater than one-quarter inch per foot. Gr, in other jvords, there is no danger of a film shrinking to such an extent that the length of sixteen pictures is less than eleven and three-quarter inches,and as this is substantially the .maximum amount to which the films shrink, l prefer to make the diameter of 'the sprocket Wheel la such thatv it Will prefectiy mesh with a iilin which is eleven and three-.quarter inches per sixteen. pictures, or having-a circumference of inches, so thatthe normal length of 'four pictures on the film is substantially greater than i the circumference of Athe sprocket wheel.'`

ln a'film n'hich has just been perforatcd,f which is exactly twelve inches in length for each' sixteen pictures, vvliile the lineal travel of the periphery et the sprocket wheel is only eleven and three-quarter inches per sii;- teen pictures, there would be a slip of about .O39 j.inch-for each tooth of. the sprocket Wheel; or, in other Words, as one tooth of the sprocket wheel disengages itself frein the opening inv the film.l the next hole in the film is advanced .O39 inch with relation to the 'tooth before the tooth engages the edge of the next perforation.

As the perforations in the film are somem what larger than the sprocket teeth, l prefer to make the circumferenceof the sprock-` et Wheel about equal to the length of four pictures at maximum shrinkage, so there is no danger of the sprocket. teeth becoming disengaged from the perlorations in the film, which might occur it' the circumference of the sprocket'ivheel Was three inches and a film shrunk one-fourth inch per foot avere fed thereby; as the sprocket teeth would then have a tendency to engage the lfilm beyond the pertorations. j

lWhen operating under the above described,

conditions l prefer to fiictionally lit) drive the take-up reel 1T to such an extent that there will be a little more than suf Vticient pull on the t'ilm to draw the film from feeding reel 15 so that only a very' slight pull of the film is exertedon the sprocket Wheel let, so that'said Wheel merely actsas a registering wheel for the successive pictures which Will reduce the Wear on 'the perforations to a negligible point. s

se arranging the film feeding mechanism ag, p i 1,573,438

that the sprocket wheel tends to move slower than the ilm, l avoid any danger of the film overrunning thesprocket wheel.

A full reel l is placed on` the spindle 16 and the e'nd of theilm is connected to the reel 16 after ,the` film has been passedy through the gate 22,` around idler" l23, measuring wheel 19 and sprocket wheel 14. T he takeup reel 17 is then rotated by hand to tale up all of the slack in the film, and the levers are then ,shifted into the position shown in Figa-4 to retain the li-lm in driving contact with the measuring and synchronizing wheel 19. rlhe motor connected to the shaft 33 is thenset in motionto drive the various parts and to notate the sproclretI wheel 14 at the proper speed to pass a predetermined number of pictures, say sixteen pictures per second, through the gate 22 and it the film is a newly perforated film, having exactly sixteen pictures to each foot oflm throughout the entire length thereof, the lineal speed of the wheel 19 will be exactly onefoot per second, and under which conditions a perfect picture, without flicker, would be projected on the screen.

As these conditions` are not .normal due to the Shrinlrageof the film, I'have provided means for automatically.'adjusting the lenses '28 and 29 relative to each other and ther film in accordance` with the film shrinkage 'or the sizes of thepicture to maintain the proj ected-picture thevsamelsize on thescreen throughout the length of the film, regardless oftheshrinhage. 'I accomplish this'in the preferred form of-my apparatus by mount-j ing the lenses 28 and 29 on movable supports which are to be arrangedtol be moved by synchronizing mechanism controlledby the variation'in speed between the measuring -wheel 19 whose lineal travel per minute is equal to the length of film passed throughA film should have Apictures of` a slightly greater length than those just mentioned, the wheel 19would speedup in proportion to the. increased length of iilm and again 'adjust the lenses28 and 29 to reduce the magnij tying power tof the projecting lens in the' proper proportion, so as to maintain a given size of picture on the screen regardless of variations in the sizes of the pictures onthe film within predetermined limits.

ln Fig. 4, l have shown Imy preferred p form of compensating mechnsm in which ported byv parallel levers 37 the lens 28 is supported in a carrier Bwhieh is pivotally mounted on a pair of parallel levers 'which are pivotally connected to the frame 10 at 38. The lens 29 which I have shown formed of two members isl also supported in a carrier 36- which is similarly suppivotally connected to the frame 10 at 38a.

These lens carriers are arranged to televscopically engage each other, while the carrier 36a is also arranged to telescopically enghge a tubular extension from the iilm gate Pivotally mounted on the spindle 20 of the measuring wheel 19 isa walking beam 39, and pivotally mounted on frame ylObef low said spindleat 40 isa lever 4l. '42 is a cam supporting frame which is pivotally connected to the walking beam 39 andthe lever' 4l in such a manner that when the walking beam is rocked theframe 42 willy be raised and lowered without varyingpthe Y angle thereof. i .v Adjustably mounted on a suitable seatlng surface on the supporting frame. 42 is a cam block 43 havinga double-faced cam 44 connected thereto,- and which is adjustably held in position on the supporting frame 42v by means of adjusting screws 45V and 46. The opposite faces of the cam'are engaged camfaces by means of a spring 47-connected by rollers on the lens carriers 36 andr, and which' rollers are held in Contact with the tothe adjacent parallel bars 37 37" The surfaces of the cam 44 engaged by the rollers are. properly shaped to move' the tol increase and :decrease the magnifying power of'vthe projecting lensln accordance with the variations in the sizes of the pic -lenses'28 and 29"toward and from each other ting upl the machine, and are not afterward adjusted except under y extraordinary conditions, as I have provided meansl for readily removing the lenses Vfor vcleansing without affecting the adjustment vx of the lenses.

Connected to the sprocket shaft lan'd arranged to rotate therewith is a gear wheel v 4S which meshes with a .gear wheel 49 on a shaft 50 mounted in bearings on the frame 10.

A51 is a gear wheel on the measuring wheel 19 vwhich meshes with ay pinion 52 on a stub' I shaft 53 carried on one end of the walking" j `beam 59.` Connected to the'pinion 52 is a beveledpinion 54 which-meshes 4with a.,

pipion- 55 on a sleeve 56 which is rotatably mounted 'on a shaft 57. The shaft 57 is carried by means of universal support 58 on the 56 andthe other mechanism.

1n driving contact with a driven disk 60 ro tatably mounted on the shaft and is arranged to be driven by the driving disk 50 through the medium of the measuring` wheel 19 and the interposed gearing. I

The hub of the driven disk SO is 'interposed between ball bearings 61 supported on the shaft 50 to eliminate friction between the shaft 50 and the disk 60 to overcome the tendency of the shaft 50 to drive the' disk 60.

Secured to the end ot' the shaft 57 is a yokel ot' nonanagnetic material which surrounds the shaft 50, which is arranged to maintain the shafts 50, 53, and 57 in alignment with each other and at the`same time permit the driving disk 59 to be moved along the face ot the driven disk 60 (o vary the ratio between said disks when the walking beam 39 is rocked as well as to permit the movement of the drivin@ disk 59 toward and Jfrom' the driven disk o8 to make and Ybreak the driving connections between the `disks 59 and 60.

63v is an electro-magnet connected to the .sleeve56 and is arranged to rotate therewith, and 64 is a conductingring connected to the sleeve 56 but insulated therefrom. The ring 6e is connected 'to one pole of the winding of the magnet 63, while 'theo'ther pole thereof is grounded through the sleeve the frame of the machine is a spring` metal conducting bush which is in engagement with the conducting ring 64 and which is connected to a source of electrical energy,

rand isarranged to conduct the current to the' magnet 63 when the circuit is closed. Asthe disks 59 and 6'), sleeve 56, shafts 50, 68 and 57, aswell as the frame, are made ot magnetic material., the disks 59 and 60 will be held in driving relation to each other by the magnetic flux when the circuit is closed through the magnet 63, and when said circuitis broken the disk 59 will be moved out otdrivin'g contact with the disk 66 by the spring brush 65 without breaking the elec- Secured to the disk 60, but insulated there? from, are adjustable contacts 71 and 72 which are electrically connected to the con 'ducting rings '66 and 67, respectively, and

which are arranged under certain conditions to close the circuit through a contact ringer Mounted on 73 rrictionally carried on the hub o gear wheel 49, and through which it is grounded to complet-e the =circuit through the motor 70. rlhe shaft of the motor 7() is provided with a line pitch worm 7st which is in engagement with ai sect'or 75 on the walking beam 39 to rock the walking beam when the motor 7 O is rotated in either direction to shift the driving disk 59 along the face of the driven disk 60 to change the ratio of the'speeds between said disks. 7 6 isa disk of magnetic material connected to the shaft or the motor 70, and 77 are electro-magnets pivotally connected to the frame of the machine and which are normally held 'from each other and the disk 76 by means of axsprinfr 78. The ,adjacent faces or the cores of t e magnets 77 are curved yat one end to form brake shoes for engaeing the disk 76 to instantaneously arrest. the movement or motor shaft and clamp it against movement when the magnets 77 are energized. rllhe magnets 77 are provided with adjustable stop screws for limiting their movement une er the action of the spring and are adapted to adjust the mag4 nets 77 so 'that the brake shoes of both magnets will be the same distance from the disk 76 when the magnets are retracted. to release the brake. v

The automatic switch for .controlli the ditlerent circuits comprises a box 80 or nonconducting material secured to the frame 10 within the drum 11, and which is provided with suitable binding posts which are interconnected with each other withinnthe boxV and with the different elements therein.

81 is a support mounted within the switch box 80, and pivotally connected to the support are two setsv of parallel levers 82, 82 and 8238?'. rl`l1e levers 82 of one set arc connected to each other by a link 83, while the levers 82a are connected to each other by means of a similar link 83.` 84; and 8i are cross bars connected to the links 83 and 83a respectively. 85 and 85L are springs connected to the respective parallel lever mechanism 'to normally move and retain the lever mechanism in their retracted positions. and 86 and 86 are electro-magnets for shifting the respective Aparallel lever mechanism against the actions ot the springs by attracting thelower parallel levers or armatures 82 and 82a.

Connected to the cross bar 84, but in-' sulated therefrom, are switch members 87, 88 and 89, and connected to the cross bar 841 are similar switch members 87"), 88a and 69a, each of which switch members is arranged to close the circuit through two contacts as hereinafter described.

90, 91, 92, 93, 9s, 95', 96, 97, 98, 99, 100' and 101 are contacts arranged in pairs and through which circuits are arranged be closed by the switch members on the cross bars 8s and Se?.

roo

. connected tothe binding' post 102.'

116, 117, 118 and 119 are binding posts Within the switch box 80, the terminals of the windings of magnet 86a are connected to the bindings posts'. 116 and 117, While the terminals of thetvindings of magnet 86 are' connected to the binding posts 118 and 119.

The binding post A103 connected to the positive pole of the source of electrical energy is also connected to the binding posts 106, 108, 116 and 118 by connections 120, While the binding post 102 which is connected tothe negative pole of the source of energy is also connected to binding' posts 107, 111 and 113 by a connection 121. The binding posts 104 and 105 are connected to binding posts 119 and 117 by Wires 122 and 123 respectively. Binding posts 104 and .105 lare also connected to brushes 68 and 69 respectively, while binding post 107 is connected to ground. Binding post 106 is con- .nected to one side of moto1124 on shaft 33 for driving the drum 11 and the sprocket Wheel 14, While the other side of said motor Visconnected to ground, or the negative pole of the source of electrical energy.

The brushes of the motor 70 for rocking the Walking beam 39 are connected to binding posts 109a and 110a which are in turn connected to binding posts 109 and 110 respectively, While the terminals of the tield windings of motor 70 are connected to binding posts 108;l and 1113, which are connected to binding posts 108 and 111 respectively. 112a and 113"L are binding posts connected to the coils of the braking magnets 77 and are alsoconnected to the binding posts 112 and 113 respectively. The binding post 106 is also connected to one side et the Winding ot ,the clutch magnet 63 through the bush 65 and ring 64, While the other side thereot1 is connected to ground` A Contacts 90, 96 and 98 are connected to the positive Wire 120 within the automatic switch box, While contacts 94 and 100 are connected to the negativejvire 121 inpsaid box.l Contacts 91 and 92 are interconnected,

.and contact 93 isconnected to binding posts 112. Contacts 95 and 99 are connected to binding posts 109 and contacts -97 and 101 are connected to binding post 110.

In the operation of the device, the film is placed as hereinbefore described and the hand switch 115 is' closed, which will close the various circuits. This closing of the different circuits Will energize the magnet 63 and draw thedriving disk 59 into driving relation with the driven disk 60, and as the motor 124 is rotated by the closing of the.

circuits, all of the film driving and synchronizing devices Will be set into motion. Assuming that the length of the film is eleven and seven-eighth inches for each sixteen pictures and all et' the various parts are in their positions for a film. of this length, the various elements will be in the positions shown in Figs. 2a11d 3, with the exception ot' the switch 115 which is closed.

As long as this ilin length is maintained,

thel circuit jto the brake magnets 77 -will remain closed and the circuit to the armature et' motor T0 for rocking the walking beam Will be open and at which time the sprocket through magnet 86 will draw down the armature or cross bar 84, break the circuit to the brake magnets 77 and free the shaft ot motor 70, and at the same time close the circuit through the motor 70 to rotate it sufticiently to shift the Walking beam 39 to move the driving disk 59 outwardly on the driven disk 60 and increase the speed ot the driven disk in directproportion to the decrease in size of the film. As soon as disk 60 lhas speeded up the circuit will be'broken tonnagnet 86 between finger 73 and contact 71. This breaking of' the circuit to magnet 86 will permit the armature or cross bar 84 to be raised by its spring 85, which will break then-.circuit to motor 70, close-the circuit to i the brake magnets 77 and arrest the movement of the shaft ot motor 70.-

` This shitting ot the-jvalking beam S9 ivill not only change the ratio between the'driving disk 59 and driven disk 60, butI it will also shift the cam frame 42 and cam 4-'1- to shift the lenses ,.28 and 29 of the projecting lens the proper distance to increase the magnification in proportiontcthe decrease in the size of the pictures on the film and therebynraintain the size of the picture projected through the compensating lens system constant. lt the tilm'length should now increase,

nar/aaa 39 to reduce the'speed ot-driven, disk GO and shift lens members28and 29 in accordance with the increase in size of the pictures ou the film. ,y

lt will', therefore` be seen that as the tilm lcngtli`varies, the lenses 2S and 29 will instantly be 'adjusted't'o vary the magnification ofthe-pictures on the .film in accordancevvith the varlations in the size 'ot said pictures to maintain a constant size ot picture projected through the compenitating lenses. as Well asthe-p`icture on the screen to and thereby avoid flicker.

ln the foregoing I have merely described a cam 4,4: for shifting the lenses 28 and 29 otthe projecting lens, having shaped surfaces on opposite faces for shifting the lenses in a machine which is spaced a given distance trom' the screen, and it it isdesired toplace thefmachine at a different distance 'from the screen than that which the cam shown is designed for, it will be necessary to provide a properly shaped cam 44. i

to equip the machinesl l prefer, however, with an adjustable cam, such as shown m Figs-13 and 14,.',Which 1isfadapted to adjust thelenses 28A and 29 of a given focal length with relation to each other to pro- 'je'c'tthe picture .on 'screens at varying disn tances Within predetermined limits. l

lin the forinshown, .the cam 44a is an irregular f :trustum .of a. cone, the surface on oneside being cut to adjust the lens carrierforlens 28, While the surface on the opposite face is cut to adjust the lens carrier forlense 29.

The sur-faces are so cut that when thecam 411e' is iniany position the lenses 28 and 29 will 'be properly adjusted yrelative to each 'other to focus the picture on a screen at a predetermined distance from the projecting lens. v

This cam 44a' isturnably mounted.v on a stem 125 extending upwardly from/a gradq uated base 126 on the cam block 43a. 12'? is a nut for securing `the cam4 to the basey block 126, and 128 is aijam nut for .locking the nut 128 against movement.

When the Amachine is vset up in the theatre, the cam @te is rotated to focus the picture on the screen and is then secured in its ad.

justedppsition on the "frame by the nuts 127 and 128, and the'screws l5 and 46, and is adapted to be adjusted by the movement ot the Walking beam 39 in @the same manner as the cam 411e to compensate orthe varia tions in the sizes oi' the ictures.'

Each of 'the lenses 28 and. 29 of the projecting. lens is mounted in a trame 129 which is seated ina reeeiving recess in its supporting frame, and is provided with a handle 130 'for removing and replacing the trame.

As the lens 29-in thc form shown is made up ot' two elements `with an intervening` space between the` members, l`prefer to mount cach member of this lens in a separate frame so that both faces ot' the two members can readily be cleaned, While the lens 2S, which is also made up ot two mehr bers the adjacent faces ot which are ccnientcd to each other, is supported in a single frame 129. rflic adjacent faces of the tivo trames 129 to; the lens members 29 engage each other, While the forward tace ot the one trame is seated against the Wall ot the receivingrecess, and 131 are leaf springs, there being one in each side of the recess, which engage the rear face of the other trame and retain both of said frames against longitudinal movement. 132 are leaf springs in one side ot the recess for the frames of the lens members of lens 29, there being one for each trame, and Which are arranged to retain the frames against the opposite Wall of the recess and also yieldingly hold said frames against i lateral movement.

The frame 129 for lens `28 is similarly retained in its recess by means of springs 131 and 132. l

This arrangement of trames and retaining springs provides means for permitting the lenses to be readily removed Jfor cleaning and accurately replaced Without changing theJ adjustment. A

in the foregoing l have` merely described one type ot electrically controlled apparatus embodyingvmy invention, but it ,'Will readily be understood that my invention may be carried out by means ototherforms ot electrically controlled and actuated devices. as

Well as with devices actuated and controlled and controlling said Vmagnification Yby the size.ot the picturesiin the film.

Another advantage results from thc pro-- vision of means for continuously moving the iilm and an optical compensating device rin synchronisin with the successive pictures on the i'ilm, and movingga,i synchronizing and stabilizer *.yheel bythe lineal travel of the iilm and adjusting the projecting lens by the variations in th'e differences 1n speed ,between the film moving means and syn# chroniaing wheel. Also lfrom the 'provision lill) of electrically actuated devices controlled by the variations in the speeds between the film feeding mechanism, and a synchronizer or measuring device actuated by the lineal speed of thefilm. j

Having now fully described myl inven tion, what I claim and desire to protect by Letters Patent is: Y K

l. The method of -projecting pictures coinprising passing a lnihaving successive pic tures in a kcontinuous manner between' a source of light and a relatively fixed lens system, moving a compensating lens system in timed 'relation to the pictures on tliefihn to compensate for the moving film, and adjusting `the lens systems with relation to each other and the film during the movement of the film to compensate for variations in the size -of said pictures.

2. The method of projecting pictures comprising passing a film having successive pictures' in a continuous manner between a source of light and a relatively fixed lens system, moving a compensating lens system in timed relation to the pictures on the film to' compensate Jfor the moving film, and adA justing the fixed lens system with relation to the' film and the movable lens systems during the movement of the film and throughout the length of its travel in proportion to the variations in the ratio between the number of pictures per given length of film and thereby vary the magnifi-v cation .thereof to maintain the projected pic- `ture'constant in size. j,

The method of projecting moving pictures ena screen, comprisingcontinuously y moving longitudinally a film having Successive pictures thereon between a source of light and a lens system fixed with relation to the continuous movement of the film, and moving the film-at a substantially constant lineal speed, moving a compensating lens system in timed lrelation to the movement'of the successive pictures through rjhich the .light passes from the fixed lens f ystem to compensate for the movement of the film to cause the picture to appear stationary on the screen, and during the longitudinal move- `ment of the ,film causing the variation between the lineal speed and the number of' pictures per given .period to vary the magnificationjin accordance with the variation in the size of the pictures to maintain a picture of constant size on the screen.-

4. The method of projecting moving pictures on a screen, comprising continuously moving longitudinally a film having succes- .sive pictures thereon between a source of light and a lens system fixed with relation tially moving a film'andan optical compensating to the continuous movement' of the film and moving-the`tilm ata substantially constant linealspeed, moving a'compensating lens ystem in timed relation to the movement of 1 the successive pictures through` which the light passes from the fixed lens system to compensate for the movement -of the film to cause thepicture to appear stationary on the screen, and during' :theI longitudinal movement of the film causing the variation between the lineal speed and the number of pictures per given period to adjust the fixed lens system with relation to the film and thc compensating lens system to maintain a picture ot constant size on the screen by var. ing the magnification in accordance with the variations iii-the sizes'of' the pictures passi ing between the source of' light and the fixed lens system.

5. The method of projecting pictures to maintain the image on the screen substantially constant in size regardless of varia tions in the size of the pictures on the film in a continuous manner, comprising moving'the film between a source of light and a magnifying medium, and a medium for compensating forthe movement of thc film and varying the magnifying medium in accordance with the variations in the sizes 'of' the pictures on the film as such variations with the variations in size.

7. The method of projecting pictures to maintainjthe image on the screen substanconstant, comprising continuously system, projecting beams of light between the film and the optical compensatingv system through an objective lens system and varying the effect of said objective lens s vstem in accordance with the variations in he length of the film picture sections to correct optically the variations in the'sizcs of. the

picture sections on the film.

In testiiiionyof which invention, I have hereunto sct my hand, at Philadelphia, Pa., on this first day of Marcin 1921.

. SAMUEL BRDY. 

